Abstract
Background and Objectives: The aim of this study was to test whether there is a necessity for routine postoperative laboratory testing in patients undergoing primary elective unilateral total knee arthroplasty (TKA), with the administration of Tranexamic Acid (TXA) and without the use of tourniquet. Materials and Methods: This observational, retrospective cohort study was conducted at Meir Medical Center. The data were collected in 2018-2022. Patients were collected in a consecutive manner. There were no exclusion criteria for this study. The inclusion criteria were individuals who underwent elective TKA due to end-stage osteoarthritis (OA). We conducted a multivariable logistic regression analysis to determine the factors associated with postoperative hemoglobin (PoOHb) < 9 g/dL and the optimal cutoff to detect those patients postoperatively. Results: A total of 271 patients were included. The mean preoperative hemoglobin (PrOHb) was 13.02 ± 1.42 g/dL, and the mean PoOHb was 11.5 ± 1.34 g/dL. The mean decrease in Hbg levels following surgery was 1.52 ± 0.91 g/dL. In all, 271 patients had a PoOHb level ≥ 9 g/dL or above. A total of 16 patients received packed red blood cells following surgery. Patients with PoOHb < 9 g/dL had a significantly lower PrOHbg. In the current study, all 11 patients who had PoOHb < 9, 10 (90.9%) had PrOHb ≤ 1011.95 55 g/dL, compared to 25 (49.6%) of the 260 patients who had PoOHb ≥ 9. The odds ratio for having PrOHb ≤ 10.9511.55 g/dL if PoOHb < 9 g/dL was 206.6710.4 (95% CI 24.427.164 to 1749.01415.97). A cut-off of 11.2510.25 would have offered a sensitivity of 99% (specificity 93.5%). Conclusions: In conclusion, this study supports using selective post-TKR Hgb monitoring rather than adhering to routine practice. An association between postoperative anemia and the need for blood transfusion was found only when the preoperative baseline hemoglobin threshold was less than 10.95 g/dL.